How can I smooth a geologic surface even if it doesn’t honor my data?

Posted by on Oct 21, 2018 in FAQ, Tips and Tricks | Comments Off on How can I smooth a geologic surface even if it doesn’t honor my data?

If I have surfaces that look like this with lots of peaks and troughs, is there an easy way to create a smooth surface, even if it doesn’t necessarily try to “honor” every point, more like a least squares fit? All of our estimation methods in krig_3d_geology honor your data, as best they can subject to your specified grid resolution.  The simplest way to get a smoother “apparent” surface is to coarsen your grid resolution.  However this method has some potential pitfalls, since the value computed at any give node will always approach the value nearest to that node.  This means that if one of your spike values (you can see that type of noise above) land very close to one of your coarse grid nodes, you can still get a spike in your coarse surface. However, there is an absolutely true way to smooth your surface regardless of grid resolution that is direct contradiction to my statement above (All of our estimation methods in krig_3d_geology honor your data). If you use the Advanced variography options in krig_3d_geology and set a non-zero nugget term, you can smooth your noisy data! I don’t have the customer’s dataset shown above, so I used one of our Sample Project datasets: This application has a DEM top surface, and a GMF file for the 4 additional stratigraphic surfaces.  After loading the app, delete these 6 modules: and after adding geologic_surfaces, change the Z Scale to 3.0 As you can see, the uppermost of our 4 surfaces is rather noisy (actually just accurately following this stratigraphic horizon, but good enough for this lesson!).   Right now we’re using Natural Neighbors with Gradients, which tends to give us the smoothest surface of all of our Estimation Methods that honors our data, but what if you wanted something much smoother? If you switch to Kriging, but don’t change anything else, you’d get: This is different, but not necessarily smoother (right)?  So let’s switch to Advance Variography and click on the Display and Edit Variogram button. To smooth our surface, we need to let the kriging DIS-honor our data.  The parameter that does that is the Nugget term.  For over 20 of our 29 years, we never let you set this parameter to a non-zero value.  Especially when dealing with environmental data (or surface data), it was our contention that the data was sacrosanct and that it should be honored.  For most sites, we still feel this is true. When the nugget term is set to zero and you use the expert system’s Defaults, they will often seem to do a poor job of fitting the variogram as shown below: First, you have to remember that the variogram fit is a constrained best-fit and second, you’re fitting the squares of the differences between your values.  When you choose a nugget term, you won’t be choosing a potential surface variation value in actual units (feet or meters), but rather the square of that value.  The nugget is a potential variance as you approach one of your data points, not a forced error. So, I will admit to having tried many different sets of values before converging on the selections below.  I even tried some Gaussian options that seemed to “fit” better, but that gave bizarre results.   So I will leave...

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Earth Volumetric Studio 2018.5

Posted by on Jun 7, 2018 in New Releases | Comments Off on Earth Volumetric Studio 2018.5

I encourage everyone to take the time to read this announcement fully, since this software release rivals the significance of the original Earth Volumetric Studio release in August 2016, and other issues mentioned in this email are critical if you want to continue to receive announcements. I won’t recap the history of C Tech as I did nearly two years ago, I’ll just focus on what is new and why it is so special. Earth Volumetric Studio 2018.5 In addition to a large number of bug fixes, stability improvements and minor enhancements, there are a few game-changing new features in this version that are sure to improve your work. When Studio first released, there were several new features as compared with MVS, such as Python scripting, fully 3D variography, and the 64-bit architecture which lifted the limits on model size. However, there weren’t many fundamentally new modeling or visualization tools until now. I’ll list them according to my personal priorities. Smooth Lithology: We’ve had adaptive_indicator_kriging for quite a while, but it has always been problematic and far from perfect, which is why we’ve deprecated it as of this release. Now, we’ve added a “Smooth” option to the indicator_geology module as well as a number of additional features such as the ability to use external grids and map lithology into multiple stratigraphic layers. The new Smooth option works perfectly.  It has no holes, it has the smoothness of stratigraphic modeling, and generally can get by with much coarser grids, while still achieving excellent results. Earth Volumetric Studio Projects 2018.5has many examples in the Lithologic Geologic Modeling folder. Real-time Editing of Stratigraphic Geology: We’ve always given you lots of options when creating stratigraphic geologic models. There are: several Estimation Methods; Thickness Space; Pinch Factor; Normal vs. Reverse Hierarchy; and even the horizon_ranking module. However, if you wanted to truly change the shape of your horizons the only option we could offer was to add additional (synthetic) points to your data file. The new edit_horizons module allows you to interactively edit any and all of your stratigraphic horizons (surfaces) by adding probed 3D points which instantaneously modify your surfaces. You’ll need to see it to believe it. Project Hand-Drawn Cross-Sections on 3D Fence Diagrams: Now that you can edit your stratigraphic geology, wouldn’t it be amazing if you could import hand-drawn cross-sections and accurately map them onto 3D fence diagrams…. and then modify your 3D geologic model to precisely match those hand-drawn cross-sections? The new texture_cross_sections module allows you to apply images along a complex non-linear thin_fence (cross-section) path and compensate for the image scale and registration points at various points along the fence path. Support for International Characters (Unicode): Until now, all of the labeling in our software has been limited to ASCII character sets. This has precluded the ability to represent more complex languages such as Chinese, Japanese, Greek, Arabic, etc. This release provides high-level support for Unicode characters when using True Type fonts in many EVS modules such as: titles; and place_text; legend (user defined only). Please note that Unicode is not yet supported in any C Tech data file formats (e.g. .pgf, .gmf, .geo, .apdv or .aidv), and therefore is not supported in the automatic labeling provided by modules like post_samples. We encourage all users to download and upgrade to Earth Volumetric Studio 2018.5 and Earth...

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The MVS Resistance

Posted by on Jan 22, 2018 in Announcements | Comments Off on The MVS Resistance

I realize that some C Tech’s MVS users are resisting migrating to Earth Volumetric Studio because they are a bit daunted by the need to use Python syntax in modules like node_computation vs. the non-standard “equation” syntax used in modules like data_math and field_math. I encourage you to submit examples of your most complex equations to and I will be preparing a short tutorial on how to use node_computation and to demonstrate just how easy it is to do these same operations in Earth Volumetric Studio. By the way.  The only modules where you need to use Python (new) syntax vs. the MVS (old) syntax are: node_computation (replaces data_math, coordinate_math and field_math):  Though I will acknowledge that it seems more difficult to have to write a Python script to do something as simple as adding, multiplying or dividing, such a script is truly trivial to create.  However, if you ever want to do something really complicated, it is now possible, where it was not before.  It goes far beyond MVS’ capabilities. format_string (replaces string_format):  The biggest issue is that it is different.  What we had before was non-standard.  You couldn’t look it up on the internet because it was unique to MVS.  What we use now is Python and it is extensible and globally accepted. trigger_script: Though it does replace link_modules it is really a new module and can do far more than link_modules could ever imagine.    It goes far beyond MVS’ capabilities. The recent Microsoft updates to Windows 7 that left many of our users temporarily unable to run their software should serve as a warning to anyone clinging to MVS.  We appreciate that when updating an old MVS project, it may be quicker (and perhaps cheaper) in the near-term to continue doing that work in MVS, but the longer you delay, the greater risk you impose on the future.  Over the past 25+ years we’ve faced numerous Windows updates that have caused catastrophic failures of various types to our software.  You can rest assured that if and when this happens we will quickly respond, as we always have.  However, we have no plans to respond to upgrade MVS.  Our focus is and will be on Earth Volumetric Studio and therefore it is imperative that all of our customers make a dedicated effort to fully transition away from...

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3D Modelling for Environmental Site Assessment

Posted by on Aug 4, 2017 in Announcements | Comments Off on 3D Modelling for Environmental Site Assessment

See the article in Remediation Magazine by Reed Copsey, C Tech’s President on “The Use of 3D Modelling for Environmental Site Assessment”.  The Use of 3D Modelling for Environmental Site...

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Free Mini Class on Advanced Visualization Techniques

Posted by on Jun 22, 2017 in Tips and Tricks | Comments Off on Free Mini Class on Advanced Visualization Techniques

C Tech will conduct a free mini-class on Advanced Visualization Techniques using Earth Volumetric Studio, on July 12, 2017 at 11:00 am EDT. We will cover some clever tricks with the buffer and union modules and some surprises.   The class was open to the first 50 registrants. It was posted Thursday June 22 and the final registrant was early Monday morning on June 26. The recorded video of the class is...

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On the death of Dr. Christopher Rautman, C Tech’s Chief Geologist

Posted by on May 22, 2017 in Announcements | Comments Off on On the death of Dr. Christopher Rautman, C Tech’s Chief Geologist

It is with great sadness that I announce that Dr. Christopher Rautman, C Tech’s Chief Geologist passed away on May 12th from complications related to an ongoing illness. I’ve known, liked, worked with and respected Chris since we first met ~20 years ago when he was at Sandia National Laboratories.  The first projects he tackled with our software included the Yucca Mountain Nuclear Repository and the salt domes and solution mined caverns used to store the U.S. Strategic Petroleum Reserves.  Over the years that Chris was at Sandia, the projects where he employed our software were some of the most challenging ones C Tech encountered, and that helped to make our software much better.  There are many important features in our software that trace back to Chris’ work and suggestions.  Under his guidance, Sandia co-funded the development of 3D Printing technology in MVS (the predecessor to Earth Volumetric Studio).  This lead to current modules like intersection, intersection_shell & union, as well as multiple enhancements to our VRML exporting which now allows us to create 3D PDFs and Sketchfab exports in addition to 3D printing.  Anyone who has used our software to model salt domes or solution mined caverns has probably worked directly with Chris, but if not, you should know that the techniques used there are directly attributable to his efforts. When Chris retired from Sandia 5 years ago, I was very excited to have him join C Tech’s team where his vast experience and keen mind was put to good use.  He took the lead on many challenging consulting projects and one of the things he could do, that I can’t imagine being able to replace, was finding, interpreting and digitizing 50-100 year old drilling records that were locked away in the archives of organizations like the Texas Railroad Commission. To see the 3D models that he created from paper drawings that were decades old is the stuff of Sci-Fi movies. I will miss Chris. I learned a great deal every time I worked with him and I counted him as a true friend. Reed Copsey, President C Tech Development...

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Free Mini-class on What’s-New in Studio 2017.3.2.

Posted by on Mar 29, 2017 in Announcements | Comments Off on Free Mini-class on What’s-New in Studio 2017.3.2.

Free Mini-class on What’s-New in Studio 2017.3.2.  More details on C Tech’s Facebook page @CTechSoftware

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Fault Surfaces in Earth Volumetric Studio

Posted by on Feb 7, 2017 in Tips and Tricks | Comments Off on Fault Surfaces in Earth Volumetric Studio

There are normally two reasons to create fault surfaces in EVS.  We either just want to display them, or we want to use them to create fault blocks as part of a more complex geologic model.  When we create fault blocks, we are using the surf_cut module and the fault surface is input to the right input port.  There are three main cases to consider with respect to the creation of fault surfaces: 1) Planar surfaces.  A planar surface is a surface which is flat.  It can be oriented in any way, but is has no curvature, bumps, etc.  This type of fault if very easy to create with the create_fault_surface module.  However, you can also cut any 3D model using the “cut” module to create a fault block. 2) Non-planar surfaces created in EVS.  There are two cases here.  Single-Valued and Multi-Valued surfaces Single-Valued or simple surfaces can be created using krig_3d_geology, krig_2d or scat_to_tin using x-y-z points formatted as .GEO, .GMF or .APDV files.  This is the easiest way to create more complex surfaces which have only ONE Z coordinate for any X-Y location. Multi-Valued surfaces are surfaces which which have TWO or more Z coordinates for any X-Y location. Some simple examples would be a sphere or a tube (pipe). Some are easily created in EVS.  For examples it is easy to create tubes of constant or variable diameter with the tubes module, and these can be used to cut tunnels through geologic models. However, in general the creation of multi-valued surfaces is a very difficult process since traditional estimation methods such as kriging, IDW, splining, TIN, etc. cannot be used.  In some cases it is possible to find a coordinate transformation where the surface would not be multi-valued. For example, imagine a cross-section through a multi-valued fault surface below.  The red line shows where this surface is multi-valued.  If we rotate counterclockwise 90 degrees, this surface is no longer multi-valued and could be created using any of our traditional methods.  All we need to do is rotate the data, create the surface and then counter-rotate the resultant surface back.  We can rotate the data using transform_field, create the TIN (or krige, etc.) , and then rotate back to the original coordinates.  Be sure to use the same center of rotation in transform_field. To confirm everything is correct, we check it against the original data.  Sometimes the angle needed is not 90 degrees, but since you don’t need to do the math yourself, it doesn’t matter.  In the case below, it would probably be better to use -75 vs. -90, since the “rotated new” left edge is nearly vertical. However:  Sometimes, there is no set of rotations that will work, as in the case of a sphere.  3) Multi-Valued surfaces created outside of EVS.  Though we don’t always provide ways to create every possible type of complex multi-valued surface, if you do have a complex multi-valued surface that was created in CAD software or by some other method, it can still be used in EVS as a fault cutting surface.  There are just a few simple requirements: The surface can be composed of triangles or quadrilateral cells.  When these cells are defined, the order that the cell’s nodes define the cells determine the normal vector of...

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Volumetrics Study: Studio vs. MVS

Posted by on Jan 18, 2017 in Tips and Tricks, Training | Comments Off on Volumetrics Study: Studio vs. MVS

Prior to the formal release of Studio, we did a comprehensive volumetrics study because we were making significant changes to both volumetrics and subsetting (e.g. plume) modules in Studio.  In that study we looked at our new Studio algorithms compared with MVS as a function of grid resolution. We’ve always known that as you increase the resolution of your model, the accuracy improves and we always see volumetrics results approach an asymptotic “theoretical” value as the grid resolution is increased. Our new algorithms in Studio work dramatically better than MVS, but we didn’t make a big deal about it, primarily out of concern that by saying that Studio is much better, we could be misconstrued as saying that MVS was somehow WRONG before.  In reality, everything we do (and by reference, everything you do with our software) is geostatistical by nature.  It is a best estimate.  And usually it is only a fair estimate because of data quality. In our study we focused on Chemical Mass (not plume volume) of the entire model, as well as X, Y, Z CG and Average Concentration.  If you additionally consider subsetting (plumes) they will effectively decrease the model resolution since the subset upon which you are computing volumetrics is a portion of your total model that has a lower effective resolution.  The higher the subsetting (plume) level, the lower the effective resolution and the poorer your results may be. The tables below summarize our results which are also given as graphs.  For both Studio and MVS we did the calculations with and without Adaptive Gridding (AG) for the total number of nodes ranging from 30,000 to nearly 8 million.  For all cases, we are computing volumetrics on the entire grid without any subsetting.   Both Studio and MVS reported exactly the same volume for the full grid which was 350,950 cubic meters.  This was not affected by resolution nor by adaptive gridding. In our study, there were very minor if any differences in volumes or plume volumes between Studio and MVS.  The biggest differences seen were in the computation of Chemical Mass and those parameters derived from chemical mass. The first, and perhaps most surprising observation of our study is how little impact (improvement) Adaptive Gridding makes for either MVS or Studio.  Adaptive Gridding does ensure that the data extremes in your 3D gridded output will better match your input data, but with respect to improving volumetrics accuracy, your time is better spent kriging a finer grid than waiting for Adaptive Gridding to finish.  The reason for this is that Adaptive Gridding refines the grid in localized areas around your data samples, but does not improve the grid globally.   As you can see, the Studio volumes are always higher than MVS, but are within 1-2% of the asymptotic value at virtually all grid resolutions.  For MVS, the volumes can be 20-25% low when the resolution is too coarse, but both Studio and MVS approach the same solution at high resolutions.. Average Concentration is derived from Contaminant Mass, and therefore is equally affected by the differences in accuracy as can be seen in the graph above. The three graphs below show the deviations in the CG or centroid of the contaminant mass in X, Y and Z.  A similar affect is seen here where Studio is markedly better at...

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Modeling of Karst Geology with Caves

Posted by on Jan 17, 2017 in Tips and Tricks | Comments Off on Modeling of Karst Geology with Caves

One of C Tech’s distributor’s in China asked us to explain how Earth Volumetric Studio could be used to model Caves. The most straightforward approach is to use indicator kriging (e.g. indicator_geology module) and treat the cave as as if it were another material in the site lithology.  The video below takes this approach.  You can also apply adaptive_indicator_kriging to stratigraphic geologic models.  In this way, if you have a site with stratigraphic geology, you can include a cave based on lithology data within the stratigraphic layers. Other approaches are to model the cave as a volumetric excavation within any type of 3D volumetric grid using either: Binary lithology (values of 1 inside the cave and 0 outside the cave).  You would format the binary data as an APDV or AIDV file and use krig_3d (turn off log processing),  or Using a closed surface created outside of Earth Volumetric Studio (such as LIDAR) and then using surf_cut I hope that this instructional video will be helpful.  The application shown here will be included in the next release of Studio Projects. Reed D. Copsey,...

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